Browsing by Author "Fernades, Filipe"
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- Influence of V concentration in TiAlSiVN coating on self-lubrication, friction and tool wear during two-pass dry turning of austenitic steel 316 LPublication . Kumar, Ch Sateesh; Urbikain, Gorka; Fernades, Filipe; Fernandes, Filipe; Rjoub, Abbas AL; Lacalle, Luis Norberto López deThe present work investigates the performance of TiAlSiVN coating with 5 and 11 at% of V concentration deposited on the Al2O3/SiC cutting tools during dry turning of austenitic 316 L stainless steel. The maximum flank wear reduction compared to the uncoated tool for coated tools with 11% and 5% V concentration was 85% and 67%, respectively. The Raman analysis indicated the formation of V2O5 in the cutting zone, which helps to reduce friction and machining forces for the coated tools. Overall, the presence of higher V content (11 at%) enhances the self-lubrication behaviour of the TiAlSiVN coating, accounting to lower fluctuations in cutting forces, superior surface finish, and lower flank wear when compared to the TiAlSiV5N coated and uncoated cutting tools.
- Microstructure evolution and mechanical behavior of magnetron sputtering AlN–Al nanostructured composite filmPublication . Ma, Bingyang; Sun, Boyuan; Li, Rongbin; Cao, Haoxin; Fernades, Filipe; Fernandes, FilipeIn this paper, a series of AlN–Al nanocomposite films are prepared by reactive magnetron sputtering. The effects of N2 flow rate on the microstructure and mechanical properties of the films are studied. The formation and evolution mechanism of the nanocomposite structure are revealed. The results show that with the decrease of N2 flow rate, the microstructure goes through three stages: pure AlN, amorphous Al surrounded nanocrystalline AlN and AlN nanoparticle reinforced Al matrix composite. Benefiting from the good wettability of Al on AlN ceramics, the film deposited at 6 sccm N2 flow rate forms a nanocomposite structure of about 8 nm AlN grains wrapped by 1–2 nm amorphous Al. The hardness of the films increases first and then decreases with the decrease of N2 flow rate, ranging from 4 GPa to 25 GPa. The toughness of the films is analyzed by the ratio of H/E, H3/E2, the normalized plastic depth (δH) and the morphology of large load indentation. The results show that the toughness of the nanocomposite film obtained at 6 sccm N2 flow rate is significantly improved while maintaining the hardness equivalent to that of pure AlN film. The improvement in toughness comes from the microcracks initiated in AlN hindered by the surrounding Al phase.
- RF magnetron sputtered Nb–V–N composite coatings for high-temperature self-lubricant applicationsPublication . Athmani, Moussa; Kong, FanLin; Ju, Hongbo; Luan, Jing; Zhang, Chengke; Ma, Bingyang; Cavaleiro, Albano; Fernades, Filipe; Fernandes, FilipeEnhancing the tribological properties of hard ceramic coatings for high temperature applications is one of the hot topics in the solid lubricant field. In this paper, a series of Nb–V–N coatings with different V concentrations were deposited using RF magnetron sputtering system, and the crystalline structure, mechanical and tribological properties were investigated. Results showed that the Nb–V–N coatings regardless of V concentrations exhibited two phase fcc-NbN with V in solid solution and hcp-NbN phase. The hardness and elastic modulus of the coatings were enhanced by adding 5.3 at.% of V. The room temperature tribological properties of the coatings were improved by the addition of V well due to the enhanced mechanical properties and the nature excellent self-lubricant characteristics. The evaluation of main tribophase from the wear track at elevated temperatures from the self-lubricant V2O3 at 400 °C to the V2O5 at 800 °C, contributed to the stable and excellent anti-frictional properties of the coating with a V concentration of 12.4 at.%. However, the wear rate of the coatings drops gradually with the increase of V concentrations due to the large amount of soft but lubricant tribophases at elevated temperatures.